Melt or bath for hardening steel.



-*n'nrrn sra'rns SHLPLEY N. BRAYSHAW, OF HULME, MANCHESTER, ENGLAND earner. oirrron.

TO GEORGE NASH, OF YORK, N. Y.

MELT OR BATH FOR HARDENENG STEEL.

Specification of Letters Patent.

Application filed March 51,1905. slain No. 253.141.

Patented Feb. 13, 1906.

1 bring them u to the desired temperature,

lead or lead al y being more commonly employed. I find that much better results may be obtained by employing a salt which is soluble in water and which is fusible at about 700 centigrade, and While sodium chlorid and potassium chlorid each separately melt at a much higher temperature than that I find that by mixing them in suitable'proportions they will melt at any desired tempera ture between 680 and 770 centigrade. My invention consists, essentially, in formmg-a melt or bath for hardening steel of sodium chlorid (NaCl) and potassium chlorid.

(KCL) tb which may be added a small proportion of potassic ferrocyanid K Fe(CN) In carrying out the invention I mix to-' gether in the desired proportions crystalline or ground sodium chlorid and potassium chlorid. This is placed in a melt-pot and gradually heated until fused in a gas or other irnace. I

The melt or bath is maintained fused when in use by the continuous application of heat from gas-jets or other flame.

The quantity or proportion of the potassium chlorid may be varied-acccording to the temperature required. The higher the temperature required the less of the potassium salt is required.

I find that in use this melt or bath will- It 1s much lighter The salt is non-poisonous.

It is much than lead and easier to handle.

cheaper than lead bulk for bulk. The arti cles sink in without being forced down. It does not form dross on the surface. It is more fluid and circulates more freely than lead. It is more gentle in its heating action than lead. It remains as a glaze over the surface of the article when removed from the melt and keeps the article hot until it is ac As soon as.

tually immersed in the water. the articles are immersed in water the Whole of the salt is removed instantly, as the salt does not adhere to the teeth or other parts of the articles as does lead.

A conspicuous advantage over potasslc cyanid is that the melt may he made carburizing by the addition of potassic ferrocyanid K Fe (CNL, or other suitable carburizing agent to any extent desired, or the melt ma be left perfectly neutrali. 45., with no ten ency .to.

carburize or to oxidize. What I claim as my invention, and desire to protect by Letters atent isl. A melt or bath for hardening tools or articles of steel comprising a fusible compound of sodium chlorid (NaCl), and potassium chlorid (KCl) substantially as described.

2.. A melt or bath for hardening tools or articles of steel comprising a compound bf several salts soluble in water, any one of which separately melts at a higher temperature. than the compound and a carburizmg agentsubstantially as described.

In Witness whereof I have hereunto slgned my name in the presence of two subscribing witnesses. v

SHIPLEY N. BRAYSl-IAVV.

Vvitnesses:

' I. OWDEN OBRIEN,

B. TABHAM WOODHEAD.

have the following advantages over leadz assrcnon 

